NASA’s newest Mars probe, MAVEN is now shooting through the solar system. A mere 440 million miles stand between the robotic explorer and its final destination: the Martian atmosphere. MAVEN launched this morning from Cape Canaveral, Florida. NASA engineers described the launch as “flawless.”

Scientists from University of California, Berkeley helped design MAVEN, or Mars Atmosphere and Volatile EvolutioN, which seeks to clues to the question: What makes Mars appear to be a barren wasteland, while Earth is verdant and full of life?

The answer may lie in Mars’ atmosphere, which is too thin to protect the planet from the Sun’s harsh glare.

Mars rovers, including Curiosity, have found telltale signs that water once flowed over the Martian surface. This suggests that Mars must once have had a thicker atmosphere, as Earth does, protecting the planet from the Sun and fostering a climate that could sustain water and maybe even life.

“The evidence for a much warmer climate in the distant past is very compelling,” says UC Berkeley space scientist David L. Mitchell. “So then the question is: Where did the atmosphere go?”

Mitchell’s team designed an instrument on MAVEN called the Solar Wind Electron Analyzer (or SEWA), which will analyze tiny particles of the Martian atmosphere, sending data about its chemical composition back to Earth.

This NASA video shows what a younger Mars may have looked like, billions of years ago when it had a thicker atmosphere and oceans of water.

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